Wireless communication apparatus and wireless communication method

ABSTRACT

A wireless communication apparatus comprising: a frame configuration circuit that generates a transmission frame including DMG beacons, wherein sector ID fields in SSW fields included in the respective DMG beacons indicate one or more transmit sectors used for directional transmissions of the respective DMG beacons, and a field different from the sector ID field included in each DMG beacon indicates whether or not there is quasi-omni transmission; and a transmission wireless circuit that performs, by using the transmit sector indicated by the sector ID field, directional transmission on a first DMG beacon that is included in the DMG beacons and in which the field different from the sector ID field indicates non-quasi-omni transmission and performs quasi-omni transmission on a second DMG beacon that is included in the DMG beacons and in which the different field indicates quasi-omni transmission, in a BTI.

This application is a continuation of U.S. patent application Ser. No.16/125,007, filed Sep. 7, 2018, now U.S. Pat. No. 10,791,453 B2, whichis a continuation of International Application No. PCT/JP2017/008879,filed Mar. 7, 2017, which claims the priority benefit of Japanese PatentApplication No. 2017-038599, filed Mar. 1, 2017, and claims the benefitof U.S. Provisional Patent Application No. 62/307,281, filed Mar. 11,2016.

BACKGROUND 1. Technical Field

The present disclosure relates to a wireless communication apparatus anda wireless communication method.

2. Description of the Related Art

In IEEE 802.11ad, a wireless communication apparatus that performswireless communication by using a millimeter waveband uses a beacontransmission interval (BTI), as described below, in a device discoveryprocedure using directional multi-gigabit (DMG) beacons.

(1) A station (which may hereinafter be referred to as a “DMG-STA” or“STA”) supporting DMG receives DMG beacons in a BTI of an access point(AP)/personal basic service set central point (PCP, which mayhereinafter be referred to as a “DMG-AP/PCP” or “AP/PCP”) supportingDMG.

(2) In a BTI of the DMG-STA, the DMG-STA transmits a DMG beacon (whichmay hereinafter be referred to as a “discovery DMG beacon”) in which adiscovery mode field is set to 1.

(3) Considering the directivity in the DMG, the BTI is constituted byone or more (a maximum of 128) DMG beacons transmitted as a transmitsector sweep.

(4) In order to reduce overhead, some fields including fields (forexample, for a service set identifier (SSID) and a DMG capability)required for discovery are omitted from DMG beacons.

Related art is disclosed in IEEE 802.11Ad™-2012, pp. 329 to 341, 10.1Synchronization.

SUMMARY

However, in communication using known millimeter wavebands, high-speeddiscovery (200 ms or less) has not been fully considered for discoveryusing DMG beacons, when the number of STAs to be discovered increases.

One non-limiting and exemplary embodiment provides a wirelesscommunication apparatus that can realize high-speed discovery (200 ms orless), even when the number of STAs that are to be discovered indiscovery using DMG beacons increases.

In one general aspect, the techniques disclosed here feature a wirelesscommunication apparatus including: a frame configuration circuit thatgenerates a transmission frame including directional multi-gigabit (DMG)beacons, wherein sector identifier fields in sector sweep fieldsincluded in the respective DMG beacons indicate one or more transmitsectors used for directional transmissions of the respective DMGbeacons, and a field different from the sector identifier field includedin each of the DMG beacons indicates whether or not there is quasi-omnitransmission; and a transmission wireless circuit that performs, byusing the transmit sector indicated by the sector identifier field,directional transmission on a first DMG beacon that is included in theDMG beacons and in which the field different from the sector identifierfield indicates non-quasi-omni transmission and that performs quasi-omnitransmission on a second DMG beacon that is included in the DMG beaconsand in which the field different from the sector identifier fieldindicates quasi-omni transmission, in a beacon transmission interval.

According to one aspect of the present disclosure, high-speed discovery(200 ms or less) can be realized even when STAs that are to bediscovered in discovery using DMG beacons increase.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a storage medium, or any selective combination thereof.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating one example of a device discoveryprocedure using DMG beacons via directional transmission according tothe present disclosure;

FIG. 2 is a diagram illustrating another example of the device discoveryprocedure using DMG beacons via directional transmission according tothe present disclosure;

FIG. 3 is a diagram illustrating an SLS in a DTI;

FIG. 4 is a diagram illustrating a configuration of an AP/PCP or a STAaccording to a first embodiment of the present disclosure;

FIG. 5 is a diagram illustrating one example of a device discoveryprocedure using DMG beacons via quasi-omni transmission according to thefirst embodiment of the present disclosure;

FIG. 6 is a diagram illustrating one example of a format of an SSW field(DMG beacon: DBcn) according to the first embodiment of the presentdisclosure;

FIG. 7 is a diagram illustrating another example of the device discoveryprocedure using DMG beacons via quasi-omni transmission according to asecond embodiment of the present disclosure;

FIG. 8 is a diagram illustrating another example of the device discoveryprocedure using DMG beacons via quasi-omni transmission according to athird embodiment of the present disclosure; and

FIG. 9 is a diagram illustrating one example of a format of an SSW field(DMG beacon: DBcn) according to the third embodiment of the presentdisclosure.

DETAILED DESCRIPTION

High-speed discovery (200 ms or less) is desirable in many applications.Thus, in order to achieve high-speed discovery, passive (static)scanning is not ideal.

In an AP/PCP, overhead increases when the frequency of a transmit sectorsweep in which discovery information is included is increased.

Thus, in active (dynamic) scanning, since beamforming is performedbefore a probe response is obtained, the discovery time increases.

FIG. 1 is a diagram illustrating one example of a device discoveryprocedure using DMG beacons via directional transmission.

In FIG. 1 , a STA executes beamforming (association beamforming training(A-BFT)). This is because a BTI does not include discovery information.The A-BFT may be omitted.

This is because overhead is added (at least 99.1 μs/BI) when the A-BFTis frequently executed. Thus, when some devices (a STA and an AP/PCP)use the A-BFT, a collision rate increases, consequently causing furtherdelay.

FIG. 3 is a diagram illustrating a sector level sweep (SLS) in a datatransfer interval (DTI). In this case, in FIG. 3 , the SLS is executedin the DTI. Although a STA can obtain discovery information via the SLSin FIG. 3 , it takes at least a few milliseconds.

FIG. 2 is a diagram illustrating another example of the device discoveryprocedure using DMG beacons via directional transmission.

In FIG. 2 , since a STA sets a discovery mode to 1 in a BTI, the STApredicts a response from a peer STA in an A-BFT; however, there arecases in which, for example, in an assigned time, collision with anotherSTA occurs, which makes it difficult for the peer STA (AP/PCP) to usethe A-BFT.

Also, the possibility that the AP/PCP gives priority to operating as abase-station apparatus is high, and there are cases in which beamformingby the STA is delayed. Thus, when a plurality of devices (STAs) attemptsto use the A-BFT, the collision rate increases, consequently causingfurther delay.

The STA does not recognize the AP/PCP until the AP/PCP startsbeamforming.

In this case, it is difficult to achieve complete omni (omnidirectional)transmission in DMG, and it is also difficult for quasi-omnitransmission to cover a sufficient range of directional transmission.The quasi-omni transmission is beam transmission to a part of an area ofomni-transmission and means transmission to a wider area than that ofdirectional transmission in which transmission is performed to onetransmit sector, that is, transmission to a plurality of transmitsectors.

First Embodiment

FIG. 4 is a diagram illustrating a configuration of an AP/PCP or a STA(wireless communication apparatus).

The AP/PCP or STA includes a control unit 101, a frame-signal generationunit 102, a frame configuration unit 103, a modulating unit 104, atransmission wireless unit 105, a transmission antenna unit 106, areception antenna unit 107, a reception wireless unit 108, ademodulation unit 109, and a frame analyzing unit 110.

The control unit 101 issues, to the frame-signal generation unit 102, aninstruction for the configuration of a frame to be transmitted andcontrols the transmission wireless unit 105 in accordance with atransmission frame to cause the transmission antenna unit 106 and thereception antenna unit 107 to execute directional transmission andquasi-omni transmission. The control unit 101 also controls thereception wireless unit 108 and the demodulation unit 109 to executereception processing. The control unit 101 reports discovery informationto an upper layer, not illustrated, and a connection command based onthe reporting is input. The connection command may be a determination atthe upper layer or may be a decision by a user. The decision by the useris input from an external input unit, not illustrated.

In accordance with an instruction from the control unit 101, theframe-signal generation unit 102 generates frame configuration signalsthat are used for a transmission frame.

The frame configuration unit 103 generates the transmission frame byusing the frame configuration signals and data.

In accordance with an instruction from the control unit 101, themodulating unit 104 generates modulated signals, for example, by using amodulation system, such as QPSK, for the transmission frame.

In order to perform directional transmission or quasi-omni transmissionfrom the transmission antenna unit 106 to an arbitrary transmit sector,the transmission wireless unit 105 performs phase adjustment on themodulated signals and performs frequency conversion on thephase-adjusted modulated signals to convert the modulated signals intowireless signals.

The transmission antenna unit 106 transmits the wireless signals viadirectional transmission or quasi-omni transmission.

By performing directional reception or quasi-omni reception in anarbitrary receive sector, the reception antenna unit 107 receiveswireless signals transmitted via directional transmission or quasi-omnitransmission. In accordance with an instruction from the control unit101, the reception wireless unit 108 performs frequency conversion toconvert the received wireless signals into baseband signals.

In accordance with an instruction from the control unit 101, thedemodulation unit 109 demodulates the baseband signals and outputs atransmission frame.

The frame analyzing unit 110 analyzes the frame configuration signalsincluded in the transmission frame and outputs discovery information (aprobe request, a probe response, and a discovery DMG beacon (DBcn)) tothe control unit 101.

FIG. 5 is a diagram illustrating one example of a device discoveryprocedure using DMG beacons via quasi-omni transmission.

A STA that executes device discovery includes quasi-omni transmission ofa DMG beacon in a BTI. A DMG beacon (DBcn) indicates that, for example,the STA is used for discovery when a discovery mode field is set to 1.One bit of each DMG beacon is used to indicate whether or not one ormore quasi-omni transmissions are included in the BTI.

The DMG beacon on which the STA performs quasi-omni transmission istransmitted by a control modulation and coding scheme (MCS). Forexample, the control MCS may be MCS 0 specified by 11ad. In thequasi-omni transmission, use of MCS 0 can increase a transmission areato a maximum degree.

FIG. 6 is a diagram illustrating one example of a format of an SSWfield. For example, 2 bits in a receive sector sweep (RXSS) lengthfield, which is reserved in a BTI, are used to indicate whether or notone or more quasi-omni transmissions are included in the BTI. An SSWfield can also be used as one constituent element of a DMG beacon in aBTI and can also be used as one constituent element of an SSW frame inan A-BFT.

In FIG. 5 , the STA transmits a quasi-omni transmission DMG beacon atleast by the end of the BTI to (implicitly or explicitly) request aprobe response from an AP.

After the AP receives DMG beacons via a plurality of directionaltransmissions and one or more quasi-omni transmissions, A-BFTbeamforming to the STA is not completed, for example, owing to collisionwith another device or conflict with a schedule of the AP.

The collision refers to a state that occurs when a plurality of peerSTAs (e.g. APs) accesses the STA at once in a limited time. Also, theconflict refers to a state that occurs when the STA that does not know aschedule performs beamforming training at an arbitrary time, althoughthere is a schedule (an order of STAs that transmit SLS) specified by anAP.

Next, in a DTI, the AP transmits a probe response via (for example, one)quasi-omni transmission to which a receive-training (TRN-R) sequence forexecuting mutual antenna training is attached. The TRN-R sequence may beswept in a range of quasi-omni transmission as directional transmission.

Upon receiving the probe response, the STA may further respond bydirectionally transmitting an ACK (acknowledge) to which the TRN-Rsequence is attached. The STA identifies a best receive sector fromreception of the TRN-R sequence, stores the best receive sector,identifies a best transmit sector from the best receive sector based onan antenna reciprocity, and stores the best transmit sector.

When the determination is successfully made in time, the STA sends anACK by using the best transmit sector; otherwise, the STA sends an ACKas quasi-omni transmission.

The AP receives the ACK, identifies a best receive sector from thereception of the TRN-R sequence, and stores the best receive sector. TheAP identifies a best transmit sector from the best receive sector, basedon an antenna reciprocity, and stores the best transmit sector.

As a result of the foregoing, the STA can use a DMG beacon frame forquasi-omni transmission included in a (DMG beacon) transmit sector sweep(TXSS) in the BTI.

A TRN sequence that is directionally transmitted for mutual antennatraining may be attached to quasi-omni transmission of a DMG beacon inthe DTI.

A probe response from a peer device (peer STA) can requested viaquasi-omni transmission of a DMG beacon.

Also, the quasi-omni transmission of the DMG beacon can indicate thatthe STA performs quasi-omni transmission.

Also, when the position of the quasi-omni transmission is fixed(example: at the end of the BTI), explicit instruction information (forexample, 1 is set for the discovery mode) does not necessarily have tobe included.

The quasi-omni transmission of the DMG beacon can indicate the number ofquasi-omni transmissions or can indicate that a plurality of quasi-omnitransmissions is included in one BTI.

The directional transmission of the DMG beacon can indicate thatquasi-omni transmission is included in a BTI/TXSS.

The directional transmission of the DMG beacon can be fragmented(fragmented) across one or more BTIs, and quasi-omni transmission of aDMG beacon may be included in one or more BTIs.

The STA that executes device discovery can transmit DMG beacons in theBTI (see FIG. 5 ).

When devices (a STA and an AP/PCP) use quasi-omni transmission for oneor more DMG beacons (see FIG. 5 ), it is possible to indicate, for theA-BFT, settings (a length/a frequency/the presence or absence/others)different from those in a case in which directional transmission is usedfor all DMG beacons (see FIGS. 1 and 2 ).

In the BTI in FIG. 5 , the device (AP) receives one or more DMG beaconstransmitted via quasi-omni transmission as a part of a transmit sectorsweep (TXSS).

In FIG. 5 , when the quasi-omni transmission is received, the device(AP) can transmit a frame (for example, a probe response or an ACKresponse) before normal beamforming exchange is performed (an SLS in theA-BFT is completed without occurrence of collision or conflict). Theframe (the probe response by the AP) to be transmitted can betransmitted via quasi-omni transmission in the control MCS.

When a probe response in the received quasi-omni transmission includes adirectional TRN sequence, the STA can directionally transmit a frame (anACK in the DTI in FIG. 5 ) to be transmitted.

The frame to be transmitted is a frame for requesting discoveryinformation or a frame including discovery information and is, forexample, a probe request, a probe response, or a discovery DMG beacon(DBcn).

In the DTI in FIG. 5 , the AP may attach a beam refinement protocol(BRP) frame for requesting/starting beam fine adjustment, instead of theTRN-R sequence, to the frame (the probe response) to be transmitted.

The frame to be transmitted can include beamforming feedback to a peerdevice, for example, a best transmit sector.

A TRN sequence directionally transmitted for mutual antenna training canbe attached to the frame to be transmitted.

When a quasi-omni DMG beacon is not received, the device (STA) may avoidquasi-omni transmission to a peer device (AP) or may avoid discovery ofa peer device and connection with a peer device.

As a result of the foregoing, the AP can discover, at high speed, thedevice (STA) in the range of quasi-omni transmission using the controlMCS.

Also, when quasi-omni transmission is included in the BTI, the peerdevice (AP) can recognize whether or not to execute discovery of adevice (STA) and connection with the device (STA).

Also, when the device (STA) includes discovery information in quasi-omnitransmission in the BTI, the peer device (AP) can discover the device(STA) with minimum overhead.

Second Embodiment

Although, in the first embodiment, the description has been given of theSTA transmitting a DMG beacon via quasi-omni transmission after DMGbeacons are transmitted via directional transmission in the BTI, adescription in the second embodiment will be given of a STA attachingone or more TRN sequences to each DMG beacon transmission viadirectional transmission.

FIG. 7 is a diagram illustrating another example of the device discoveryprocedure using DMG beacons via quasi-omni transmissions.

In a BTI in FIG. 7 , first, a STA that executes device discoveryattaches one or more TRN sequences to each directional-transmission DMGbeacon in a BTI and performs quasi-omni transmission on eachdirectional-transmission DMG beacon by using the control MCS.

The DMG beacon indicates that, for example, it is used for discoveringby a STA when the discovery mode field is set to 1, and that also a1×TRN (example: transmit training (TRN-T)) sequence attached in aphysical (PHY) header. The TRN-T may be a plurality of sequences.

The DMG beacon implicitly or explicitly requests a probe response froman AP.

Next, the AP receives one or more directional-transmission DMG beaconsand one or more TRN-T sequences respectively attached thereto andrecognizes that one or more TRN-T sequences are to be used in quasi-omnitransmissions.

Next, in a DTI, the AP transmits probe responses, for example, via aplurality of quasi-omni transmissions.

The STA receives the probe responses. When the STA responds with an ACK,the AP receives the ACK.

This allows beamforming training (TRN) sequences to be attached to aplurality of DMG beacons directionally transmitted in the BTI, even whencollision or conflict occurs in an A-BFT.

The transmission of the TRN sequences can also be fragmented across aplurality of BTIs, that is, the TRN sequences can also be transmitted ina BTI following a DTI.

A DMG beacon to which quasi-omni transmission of a TRN sequence isattached and that is to be directionally transmitted does notnecessarily have to explicitly indicate that quasi-omni transmission isused for the TRN sequence.

Also, the STA can request a probe response from a peer device by usingthe DMG beacon to which quasi-omni transmission of the TRN sequence isattached and that is to be directionally transmitted.

As a result of the foregoing, a device in the range of quasi-omnitransmission using the control MCS can be discovered at high speed andwith high priority.

When the quasi-omni transmission is included in the BTI, a peer devicecan recognize whether or not discovery of a device/connection with adevice is to be executed.

When discovery information is included in quasi-omni transmission in theBTI, the AP can discover the device (STA) with minimum overhead.

Third Embodiment

In a third embodiment, a description will be given of transmission of aDMG beacon via quasi-omni transmission by an AP in a BTI.

FIG. 8 is a diagram illustrating another example of the device discoveryprocedure using DMG beacons via quasi-omni transmission.

An AP includes one or more quasi-omni transmissions for DMG beacons in aBTI. By using 1 bit of each DMG beacon, the DMG beacon indicates whetheror not quasi-omni transmission is included in the BTI. By using 1 bit ofeach DMG beacon, the DMG beacon may indicate whether or not a frame is aquasi-omni transmission. A transmit sector of the quasi-omnitransmission of each DMG beacon may differ for each transmission.

FIG. 9 is a diagram illustrating one example of a format of an SSWfield. One bit of a quasi-omni transmission DMG beacon, for example, 3bits of an RXSS length field (reserved in a BTI), is used to indicate aplurality of quasi-omni transmissions. The SSW field can also be used asone constituent element of a DMG beacon in a BTI and can also be used asone constituent element of an SSW frame in an A-BFT.

The quasi-omni transmission DMG beacon is transmitted at the beginningof a BTI and includes an SSID, a DMG capability, and other informationfor prompt discovery, and a TRN-R sequence used for mutual antennatraining is attached to the quasi-omni transmission DMG beacon. TheTRN-R sequence is, for example, directionally transmitted in a range ofquasi-omni transmission.

In order to reduce the duration of the BTI, the SSID, the DMGcapability, and the other information may be omitted in adirectional-transmission DMG beacon transmitted at a stage subsequent tothe quasi-omni transmission DMG beacon.

Next, the STA receives DMG beacons, which are one or more quasi-omnitransmissions and one or more directional transmissions, identifies abest receive sector from reception of a TRN-R sequence directionallytransmitted in the range of the quasi-omni transmissions, and stores thebest receive sector. The STA identifies a best transmit sector from thebest receive sector, based on an antenna reciprocity, and stores thebest transmit sector.

The STA reports discovery information to, for example, an upper layer orconnection management software, such as Supplicant, and receives aconnection command for an AP/PCP from the upper layer, the connectionmanagement software, or a user.

Next, in a DTI, by performing directional transmission, the STAconnects, to the AP, an association request to which a TRN-R sequence isattached. The STA performs quasi-omni transmission on the TRN-Rsequence.

The AP receives the association request via quasi-omni reception,identifies a best receive sector from reception of the TRN-R sequence,and stores the best receive sector. Based on the antenna reciprocity,the AP identifies a best transmit sector from the best receive sector,and stores the best transmit sector.

The AP directionally transmits an ACK in response to the associationrequest from the STA and then responds to the request from the STA bytransmitting an association response.

The STA receives the ACK and the association response that correspond tothe association request and responds with an ACK in response to theassociation response from the AP.

When the AP receives the ACK that corresponds to the associationresponse, the STA and the AP complete connection establishment.

As a result of the foregoing, quasi-omni transmission can be performedon a DMG beacon frame, or a beamforming training (TRN) sequence to bedirectionally transmitted can be attached to a DMG beacon frame.

A TRN sequence to be directionally transmitted for mutual antennatraining may be attached to quasi-omni transmission of a DMG beacon in aBTI.

Also, when the position of a quasi-omni transmission is fixed (example:the beginning of a BTI), explicit instruction information does notnecessarily have to be included.

For example, when the A-BFT is omitted, additional information used fordiscovering a device can be included in a quasi-omni transmission.

A DMG beacon quasi-omni transmission including the additionalinformation can be transmitted at the beginning of the BTI. This allows,for example, a legacy device to analyze the additional information.

The device (STA) can use a frame to be transmitted as a linkestablishment frame (example: an association request).

As a result of the foregoing, a device in the range of quasi-omnitransmission using the control MCS can be discovered at high speed andwith high priority.

When quasi-omni transmission is included in the BTI, the peer device(AP) can recognize whether or not discovery of a device/connection witha device is to be executed.

When discovery information is included in the quasi-omni transmission inthe BTI, the peer device (AP) can discover the device (STA) with minimumoverhead.

By using the quasi-omni transmission and the directional TRN sequence,the peer device can reduce the beamforming time, since the A-BFT can beomitted.

The device can give priority to discovery of a peer device/response to apeer device, when the peer device uses a plurality of quasi-omnitransmissions.

Although, in each embodiment described above, the present disclosure hasbeen described in conjunction with an example in which it is configuredusing hardware, the present disclosure can also be realized by softwarein cooperation with hardware.

Also, the individual functional blocks used in the description of eachembodiment described above are typically realized as a large-scaleintegrated (LSI) circuit. The integrated circuit may control theindividual functional blocks used in the description of each embodimentdescribed above and may have an input and an output. The functionalblocks may be individually realized by single chips or may be realizedby a single chip so as to include some or all of the functional blocks.Although the functional blocks are implemented by an LSI in this case,they may also be called an integrated circuit (IC), a system LSI, asuper LSI, or an ultra LSI depending on a difference in the degree ofintegration.

The scheme for integrating the functional blocks into an integratedcircuit is not limited to a scheme for LSI and may be realized using adedicated circuit or a general-purpose processor. The scheme for theintegration may also utilize a field programmable gate array (FPGA) thatcan be programmed after manufacture of an LSI or a reconfigurableprocessor that allows reconfiguration of connections or settings ofcircuit cells in an LSI.

In addition, when a technology for circuit integration that replaces LSIbecomes available with the advancement of semiconductor technology oranother derivative technology, such a technology may also naturally beused to integrate the functional blocks. Application of biotechnology orthe like is possible.

Various aspects of the embodiments according to the present disclosureinclude the followings.

A wireless communication apparatus according to a first disclosure ofthe present disclosure includes: a frame configuration circuit thatgenerates a transmission frame including directional multi-gigabit (DMG)beacons, wherein sector identifier fields in sector sweep fieldsincluded in the respective DMG beacons indicate one or more transmitsectors used for directional transmissions of the respective DMGbeacons, and a field different from the sector identifier field includedin each of the DMG beacons indicates whether or not there is quasi-omnitransmission; and a transmission wireless circuit that performs, byusing the transmit sector indicated by the sector identifier field,directional transmission on a first DMG beacon that is included in theDMG beacons and in which the field different from the sector identifierfield indicates non-quasi-omni transmission and that performs quasi-omnitransmission on a second DMG beacon that is included in the DMG beaconsand in which the field different from the sector identifier fieldindicates quasi-omni transmission, in a beacon transmission interval.

The wireless communication apparatus according to a second disclosure ofthe present disclosure, including: a reception wireless circuit thatreceives, in a data transfer interval (DTI), a probe responsetransmitted via quasi-omni transmission and a sequence signal used formutual antenna training from a communication partner to which the DMGbeacons were transmitted; and a control circuit that selects, from theone or more transmit sectors, a transmit sector corresponding to areceive sector of the communication partner, the receive sector beingindicated by the sequence signal.

In a wireless communication apparatus according to a third disclosure ofthe present disclosure, the frame configuration circuit generates anacknowledge (ACK) signal corresponding to the probe response; and thetransmission wireless circuit performs directional transmission on theACK signal by using the selected transmit sector.

A wireless communication method according to a first disclosure of thepresent disclosure including: generating a transmission frame includingdirectional multi-gigabit (DMG) beacons, wherein sector identifierfields in sector sweep fields included in the respective DMG beaconsindicate one or more transmit sectors used for directional transmissionsof the respective DMG beacons, and a field different from the sectoridentifier field included in each of the DMG beacons indicates whetheror not there is quasi-omni transmission; and performing, by using thetransmit sector indicated by the sector identifier field, directionaltransmission on a first DMG beacon that is included in the DMG beaconsand in which the field different from the sector identifier fieldindicates non-quasi-omni transmission, and performing quasi-omnitransmission on a second DMG beacon that is included in the DMG beaconsand in which the field different from the sector identifier fieldindicates quasi-omni transmission, in a beacon transmission interval.

The present disclosure is desirable for use in wireless communicationapparatuses.

What is claimed is:
 1. A communication apparatus comprising: receptioncircuitry which, in operation, receives a transmission frame including aplurality of directional multi-gigabit (DMG) beacons for transmissionbeam training and receives a Probe Request for device discovery beforeperforming the transmission beam training, wherein the plurality of DMGbeacons are transmitted as multiple directional transmissions and theProbe Request is transmitted with quasi-omni transmission from acommunication partner apparatus; and transmission circuitry which, inoperation, transmits a Probe Response via quasi-omni transmission inresponse to the Probe Request that is received before performing thetransmission beam training.
 2. The communication apparatus according toclaim 1, wherein the reception circuitry, in operation, receives a framevia directional transmission after transmitting the Probe Response. 3.The communication apparatus according to claim 1, wherein the ProbeRequest is received after receiving the plurality of DMG beacons withina Beacon Transmission Interval (BTI).
 4. The communication apparatusaccording to claim 1, wherein the reception circuitry, operation,receives an ACK frame transmitted via directional transmission from thecommunication partner apparatus, after the transmission circuitrytransmits the Probe Response with a TRN-R sequence.
 5. A communicationmethod for a communication apparatus comprising: receiving atransmission frame including a plurality of DMG beacons for transmissionbeam training and receiving a Probe Request for device discovery beforeperforming transmission beam training, wherein the plurality of DMGbeacons are transmitted as multiple directional transmissions and theProbe Request is transmitted with quasi-omni transmission from acommunication partner apparatus; and transmitting a Probe Response viathe quasi-omni transmission in response to the Probe Request that isreceived before performing the transmission beam training.
 6. Thecommunication method according to claim 5, comprising: receiving a framevia directional transmission after transmitting the Probe Response. 7.The communication method according to claim 5, wherein the Probe Requestis received after receiving the plurality of DMG beacons within a BeaconTransmission Interval (BTI).
 8. The communication method according toclaim 5, comprising: receiving an ACK frame transmitted via directionaltransmission from the communication partner apparatus, aftertransmitting the Probe Response with a TRN-R sequence.